IC 59 and IC 63 In Cassiopeia

Over the last few years, a wave of CMOS detectors has hit the market at the expense of the more “traditional” CCD ones. I will not delve into the technical details, but after On Semi’s recent announcement about the abrupt discontinuation of the entire KAF and KAI CCD product line in 2020 it really looks like that the days of CCD are coming to an end. CCD sensors will most likely remain for high-end niche applications, but CMOS sensors are bound to take over the amateur astronomy market.

CMOS sensors do have some advantages over their “older siblings” such as very low read noise and fast readout times. Even if most CMOS-based cameras do not offer 16-bit output, the low read noise yields a dynamic range comparable (or sometimes better) to that of most CCD detectors.

Back in September 2019, I decided to bite the bullet and purchased a CMOS color camera, the ASI 071MC Pro. Built around the Sony IMX 071 detector, the ASI features 16 Mp resolution, 14-bit output and a relatively wide APS-C format.

To put my new camera through its paces, I decided to image a rather difficult target, IC 59 and IC 63, two emission/reflection nebulae located near gamma Cassiopeiae. This is not the first light image for my new puppy :-), but it is a very demanding challenge as these two nebulae are very faint and elusive. Here is the result:

I must say that all in all I am quite pleased with the outcome, although color detectors (CCD and CMOS alike) are not ideal for faint targets, where mono cameras (with narrowband filters for better contrast on emission nebulae) yield much better results, regardless of the type of detector used.

Enjoy! :-)